The Pilgrims' side, predominantly an under-17s line-up, lost 2-1 at home to Morpeth Town.
Freddie Shinn was United's goalscorer during the second half.
Boston: Sam Buckland, Aron Ealham, Sean Bray-Smith (Daniel Fisk 85), Toby Cotton, Charlie Brooks, Elod Nadasdi, Will Pettitt, Jake Thompson, Freddie Shinn (Denis Matei 65), Josh Panton, Sam Finch. Subs (not used): Tyreece Keating, Toby Foreman, Jack Dixon.
Referee: Trevor Basker.